The year was 1889. The War of the Currents was well underway. At stake: the future of electrical power distribution on planet Earth. With the financial backing of George Westinghouse, Tesla’s AC polyphase system competed for market dominance with Edison’s established (but less efficient) DC system, in one of the ugliest and most epic tales of technological competition of the modern age.

More than a hundred years after the dust settled, Matt Fraction and Steven Sanders published The Five Fists of Science: a rollicking graphical retelling of what really happened at the turn of the last century. (Get yourself a copy and read it immediately, unless you’re allergic to AWESOME). On the right is the cover to this fantastic tale of electrical fury.

See that dapper fellow in front? That’s a young Mr. Tesla. See what he’s packin’?

I gave another talk at Ada’s Technical Books: this time about the (nearly completed) Tesla gun. The audio isn’t perfect, and it very tragically ends just before the spectacular spark demonstration, but here it is:

After tragically melting my previous HV switch, and given that a 15kV multi-ampere switch isn’t exactly something you find at Radio Shack, I’ve had to resort to more drastic measures. It was time to make one from scratch.

The fine folks at Metrix CreateSpace had just to tools I needed: a 3D powder printer to make a slip cast mold, and a kiln to fire the clay into porcelain. After a couple of revisions, I settled on something vaguely resembling a cooling tower. This will let me install a tiny turbine in the bottom to pull out hot ions, while using a minimum amount of material for the switch itself.

Install some tungsten welding electrodes (held in place with high temperature silicone) and voila: a handy switch capable of handling a couple of kilowatts at 15+kV!

Did I mention that, given the incompressibility of porcelain and the shape of the cooling base, it is perhaps a little loud?

I’ve made a little progress with the mini-coil. I have two flyback drivers up and running. Each circuit fits nicely inside a 2″ ABS cup potted with silicone, now dubbed the hockey puck of DOOM.

One flyback charges a capacitor bank, and is held open by the trigatron. I’m not sure when these actual trigatrons where manufactured, but they’ve been available since the 1940s.

The trigatron acts as a very quiet, easily controlled spark gap switch. When the second flyback turns on, it closes the switch, dumping the charge in the capacitor bank across the primary of the Tesla coil.

When actually operating, both coils will charge the bank in parallel, and the trigatron will be fired with very precise timing using a solid state ignition coil.

I’m working on a small Tesla coil project. After hours of winding and letting the polyurethane cure, there’s nothing quite like the thrill of finding the resonant frequency of your secondary + top load… 423 kHz for this little guy!